“The Staircase” director Jean-Xavier de Lestrade on the Michael Peterson murder case, his ethical struggle, and the owl theory

The granddaddy of true-crime docuseries, “The Staircase” follows the 2001 death of Kathleen Peterson and subsequent murder trial of her husband, novelist Michael Peterson.

The case’s core question was how Kathleen Peterson actually died: Was she beaten to death with a metal fireplace tool, as the prosecutors in Durham, North Carolina contended, or did a violent fall result in that gruesome, bloody scene at the foot of their stairs?

It was never a simple question to start with, and the trial — documented in “The Staircase’s” first eight episodes, which originally aired in 2004 — introduced twists and turns that beggared belief, including Michael Peterson’s strange manner, his secret affairs with men, and another dead woman at the foot of a different set of stairs.

But the story didn’t end with that trial. Subsequent legal proceedings necessitated new “Staircase” installments in 2013, and Netflix recently released three more new episodes, bringing the total to 13.

The entire 16-year saga was directed by Jean-Xavier de Lestrade, the French filmmaker whose “Murder on a Sunday Morning” won an Academy Award for Best Documentary Feature in 2001.

Watching “The Staircase,” it’s clear that de Lestrade got close to his subject, spending hours and hours with Peterson and his lead defense attorney, David Rudolf. Though the series stops short of advocating for Michael Peterson — not exactly, anyway — it does allow Peterson to offer a more nuanced position than he could have in more traditional press.

What “The Staircase” almost entirely ignores, though, is the “owl theory” that was posited late in the trial and sounded too crazy to be true: that Kathleen Peterson wasn’t murdered by Michael Peterson, but was rather attacked by a bird.

Vulture caught up with de Lestrade and Rudolf to talk about the show’s history, the difficulty of making a truly objective documentary, and, yes, that owl.